Robotic Spray System

This specification is based upon and claims the benefit of priority from United Kingdom patent application number GB 2418581.1 filed on Dec. 18, 2024, the entire contents of which is incorporated herein by reference.

The present disclosure relates to a robotic spray system, more specifically a hyper-redundant manipulator spray system and a method for depositing a coating material on a component that is located within a gas turbine engine.

Spray coatings are used in a number of industries to supply a thin deposition of material onto a substrate. The material to be coated is typically supplied in suspension in a solvent and passed through a nozzle to propel it onto the target substrate.

Despite spray coating being generally well-known many issues still arise with respect to what materials are suitable for spray coating and what equipment is available to apply such materials to particular substrates. Such issues are exacerbated when using applying spray coating technologies to repair complex machines such as gas turbine engines, especially gas turbine aircraft engines, where the coating is typically required at a location that is generally inaccessible without stripping at least part of the engine and where the accuracy and effectiveness of the repair is critical to the safety of the passengers and the crew of an aircraft that is powered by the engine. The need to provide the necessary tooling for the spray coating typically means removing the component from the engine and taking it to specialist thermal spraying equipment to be suitably coated.

When spray coating gas turbine engines the coating is typically an engineering coating that is applied to a turbine blade or vane and the engineering coating material is often a yttrium-stabilized zirconia (YSZ), which is deposited using customary engineering spraying methodologies, notably atmospheric plasma spraying (APS), high-velocity oxy-fuel (HVOF) spraying, or suspension plasma spraying (SPS).

If the engineering coating becomes worn or damaged the turbine blade or vane needs to be removed. APS deposition involves exposing YSZ powder to an exceedingly high-temperature plasma, after which it is propelled onto the relevant surface of the component, where it solidifies quickly and forms layers. Upon impact with the surface, particles within the engineering coating material disperse and the coating solidifies. The equipment that is currently used for APS, HVOF and SPS deposition is too large to be used in an in situ setting within a gas turbine engine and it typically requires using atmospheric controlled booths with furnaces.

Consequently, there is a need to provide an improved method and system for applying engineering coating materials to components within a gas turbine engine.

In a first aspect a hyper-redundant manipulator spray system for depositing an engineering coating material on a component that is located within a gas turbine engine, the hyper-redundant manipulator spray system comprises: a hyper-redundant manipulator arm that has a proximal end and a distal end; an end effector that is located at the distal end of the hyper-redundant manipulator arm, the end effector having an atomizing nozzle unit and a burner head, the burner head having a supply of a flammable fluid; an actuator pack that is located at the proximal end of the hyper-redundant manipulator arm and controls movement of the hyper-redundant manipulator arm; and a tank for holding the engineering coating material to be deposited on the component; wherein the burner head has at least one jet and an air nozzle, the burner head being configured to combust the flammable fluid supplied by the supply of flammable fluid and eject the combusted flammable fluid from the jet to form a combustion zone around a resulting flame, the air nozzle being aligned with the jet to direct a flow of air from a supply of air towards the component; and the atomizing nozzle unit is configured to receive a supply of a suspension of engineering coating material from the tank and is provided with a pressurised gas feed to atomize the material, the atomizing nozzle unit being positioned to direct a spray of the engineering coating material into the flame provided by the burner head that propels the spray of the engineering coating material on to the component upon which the engineering coating material solidifies.

In some embodiments the tank has an agitation device for stirring or otherwise agitating the suspension of thermal coating barrier material within the tank.

15 In some embodiments the air nozzle provides a flow of air at a pressure of from 120 to 1500 kPa (1.2 tobar).

In some embodiments a conduit connects the tank and the atomizing nozzle unit and a flow regulator is provided for maintaining a constant flow rate of engineering coating material between the tank and the atomizing nozzle unit.

In some embodiments the flow regulator is formed or located in the conduit that connects the tank and the atomizing nozzle unit.

In some embodiments the tank is located at or near the proximal end of the hyper-redundant manipulator arm.

In some embodiments a flow of air is supplied to the atomizing nozzle unit from a source of air to atomize the suspension of engineering coating material within the atomizing nozzle unit.

15 In some embodiments the flow of air is supplied to the atomizing nozzle unit at a pressure of from 120 to 1500 kPa (1.2 tobar)

In some embodiments the atomizing nozzle unit has a pressure regulator that regulates the flow of atomized engineering coating material from the atomizing nozzle unit into the combustion zone.

In some embodiments the pressure regulator provides the engineering coating material into the combustion zone at a flow rate of from 0.5 to 50 ml/min.

In some embodiments the atomizing nozzle unit has an atomizing nozzle unit outlet that is positioned to spray the engineering coating material from 5 to 75 mm above the flame plume.

In some embodiments the atomizing nozzle unit is configured to spray the engineering coating material at an angle to the flame.

In some embodiments the atomizing nozzle unit is configured to spray the engineering coating material perpendicular to the flame.

In some embodiments the atomizing nozzle unit is configured to spray the engineering coating material in line with the flame.

In some embodiments the end effector is coupled to the hyper-redundant manipulator arm with a rotatable coupling and a drive motor is provided that enables the end effector to oscillate its orientation relative to the hyper-redundant manipulator arm.

In some embodiments the engineering coating material is an environmental barrier coating material for forming an environmental barrier coating (EBC) on the component.

In some embodiments the engineering coating material is a thermal barrier coating material for forming a thermal barrier coating on the component.

In a second aspect a method for depositing an engineering coating material on a component that is located within a gas turbine engine is provided. The method comprises the steps of: providing the hyper-redundant manipulator spray system of the first aspect; positioning the hyper-redundant manipulator arm of the hyper-redundant manipulator spray system within a workspace in which the component is located; supplying a flammable fluid to at least one jet of the burner head and combusting the flammable fluid to form a flame; supplying a suspension of an engineering coating material to the atomizing nozzle unit and directing a spray of atomized engineering coating material into the flame; moving the end effector along a path to deposit the engineering coating material from the flame on the component; and turning off the supply of the flammable fluid to the at least one jet of the burner head and the supply of the suspension of the engineering coating material to the atomizing nozzle unit.

In a third aspect a method for depositing an engineering coating material on a component that is located within a gas turbine engine is provided. The method comprises the steps of: providing the hyper-redundant manipulator spray system of the first aspect with the atomizing nozzle unit having a pressure regulator that regulates the flow of atomized engineering coating material from the atomizing nozzle unit into the combustion zone; positioning the hyper-redundant manipulator arm of the hyper-redundant manipulator spray system within a workspace in which the component is located; supplying a flammable fluid to at least one jet of the burner head and combusting the flammable fluid to form a flame; supplying a suspension of an engineering coating material to the atomizing nozzle unit and directing a spray of atomized engineering coating material into the flame; moving the end effector along a path to deposit the engineering coating material from the flame on the component; and turning off the supply of the flammable fluid to the at least one jet of the burner head and the supply of the suspension of the engineering coating material to the atomizing nozzle unit.

The present disclosure provides a hyper-redundant manipulator spray system and method for depositing an engineering coating material on a component that is located within a gas turbine engine. The gas turbine engine may take various forms. For example, the gas turbine engine may comprise an engine core comprising a turbine, a combustor, a compressor, and a core shaft connecting the turbine to the compressor. Such a gas turbine engine may comprise a fan (having fan blades) located upstream of the engine core. The gas turbine engine may have a gearbox that receives an input from the core shaft and outputs drive to the fan so as to drive the fan at a lower rotational speed than the core shaft.

The term “hyper-redundant manipulator” as used herein is a continuously bending actuatable structure with an extremity fixed to a base that contain actuations and control hardware.

The term “hyper-redundant manipulator arm” as used herein means an arm of a hyper-redundant manipulator.

The term “actuator pack” as used herein means that part of a hyper-redundant manipulator that controls movement of a hyper-redundant manipulator arm. The movement of the hyper-redundant manipulator arm is typically achieved by tensioning or relaxing a plurality of actuators, e.g. in the form of tendons that run through the joints of the hyper-redundant manipulator arm.

The term “end effector” as used herein means that part of a hyper-redundant manipulator arm that includes tooling and/or inspection equipment for the function of the hyper-redundant manipulator arm is intended to perform.

The term “component” as used herein means a part of a machine such as a gas turbine engine. The component may be a gas turbine aircraft engine component. The component may be formed from a base material, for example a titanium-based superalloy or a nickel-based superalloy.

The term “engineering coating” as used herein means a coating that alters the surface properties of the substrate to which it is applied. It may be a thermal barrier coating (TBC) i.e. a thermally insulating material that is applied to a substrate that is typically exposed to elevated temperatures, or an environmental barrier coating (EBC) i.e. a barrier coating that is applied to a substrate that is typically exposed to environmental stresses such as icing and erosion.

The term “engineering coating material” as used herein is material from which an engineering coating is formed. It is typically applied to the surface of a component, e.g. a gas turbine engine component, that requires protection to extending component life. An engineering coating material may be an environmental barrier coating material from which an environmental barrier coating may be formed or it may be a thermal barrier coating material from which a thermal barrier coating may be formed.

The term “environmental barrier coating” or “EBC” as used herein is a barrier coating that is applied to a substrate that is typically exposed to environmental stresses such as icing and erosion. Environmental barrier coatings are typically applied to gas turbine engine components to increase their service life. They tend to be stabilized ceramics that can sustain a fairly high temperature gradient. They are often used to prevent water vapour degradation of gas turbine engine components that are made from SiC-SiC ceramic matric composite materials (CMCs).

The term “thermal barrier coating” or “TBC” as used herein is a barrier coating that is applied to a substrate that is typically exposed to elevated temperatures. Such coatings can allow for higher operating temperatures while limiting the thermal exposure of structural components, extending component life by reducing oxidation and thermal fatigue.

The term “flame spray” as used herein is a process that uses an oxy-fuel flame to melt wires and in some cases powders or ceramic rods. The molten material is then atomised with compressed air to create a spray stream that applies a coating onto a surface being sprayed.

Throughout this specification and in the claims that follow, unless the context requires otherwise, the word “comprise” or variations such as “comprises” and “comprising”, will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other stated integer or group of integers.

The skilled person will appreciate that except where mutually exclusive, a feature described in relation to any one of the above aspects may be applied mutatis mutandis to any other aspect. Furthermore, except where mutually exclusive any feature described herein may be applied to any aspect and/or combined with any other feature described herein.

Aspects and embodiments of the present disclosure will now be discussed with reference to the accompanying drawings. Further aspects and embodiments will be apparent to those skilled in the art.

The present disclosure provides a hyper-redundant manipulator spray system and method for depositing an engineering coating material on a component that is located within a gas turbine engine. While thermal spray coating has been commonly used to apply protective coatings to various substrates the technique is generally not suitable when the substrate is located within a confined or otherwise restricted space. This is because of difficulties in bringing the necessary equipment to the relevant workspace and accurately the thermal spray coating material to the relevant substrate within that workspace. These difficulties often mean the component that requires coating or coating repair must be removed from the engine and taken to specialist thermal spraying equipment to be suitably coated. Such requirements increase both the cost of repair and the length of down time for the gas turbine engine from which the component was removed.

The hyper-redundant manipulator spray system of the present disclosure is able to deposit sub-micron or even nano size particulates using miniature combustion flame spray technology to achieve durable nano-structed coating from suspension feedstock.

Referring now to the drawings:

1 FIG. 10 9 10 12 23 10 11 11 14 15 16 17 19 20 21 10 22 18 22 23 19 26 30 illustrates a gas turbine enginehaving a principal rotational axis. The enginecomprises an air intakeand a propulsive fanthat generates two airflows: a core airflow A and a bypass airflow B. The gas turbine enginecomprises a corethat receives the core airflow A. The engine corecomprises, in axial flow series, a low pressure compressor, a high-pressure compressor, combustion equipment, a high-pressure turbine, a low pressure turbineand a core exhaust nozzle. A nacellesurrounds the gas turbine engineand defines a bypass ductand a bypass exhaust nozzle. The bypass airflow B flows through the bypass duct. The fanis attached to and driven by the low pressure turbinevia a shaftand an epicyclic gearbox.

14 15 15 16 17 19 20 17 15 27 23 30 In use, the core airflow A is accelerated and compressed by the low pressure compressorand directed into the high pressure compressorwhere further compression takes place. The compressed air exhausted from the high pressure compressoris directed into the combustion equipmentwhere it is mixed with fuel and the mixture is combusted. The resultant hot combustion products then expand through, and thereby drive, the high pressure and low pressure turbines,before being exhausted through the core exhaust nozzleto provide some propulsive thrust. The high pressure turbinedrives the high pressure compressorby a suitable interconnecting shaft. The fangenerally provides the majority of the propulsive thrust. The epicyclic gearboxis a reduction gearbox.

23 26 23 23 Note that the terms “low pressure turbine” and “low pressure compressor” as used herein may be taken to mean the lowest pressure turbine stages and lowest pressure compressor stages (i.e. not including the fan) respectively and/or the turbine and compressor stages that are connected together by the interconnecting shaftwith the lowest rotational speed in the engine (i.e. not including the gearbox output shaft that drives the fan). In some literature, the “low pressure turbine” and “low pressure compressor” referred to herein may alternatively be known as the “intermediate pressure turbine” and “intermediate pressure compressor”. Where such alternative nomenclature is used, the fanmay be referred to as a first, or lowest pressure, compression stage.

1 FIG. 18 20 22 18 20 22 11 10 30 Other gas turbine engines to which the present disclosure may be applied may have alternative configurations. For example, such engines may have an alternative number of compressors and/or turbines and/or an alternative number of interconnecting shafts. By way of further example, the gas turbine engine shown inhas a split flow nozzle,meaning that the flow through the bypass ducthas its own nozzlethat is separate to and radially outside the core exhaust nozzle. However, this is not limiting, and any aspect of the present disclosure may also apply to engines in which the flow through the bypass ductand the flow through the coreare mixed, or combined, before (or upstream of) a single nozzle, which may be referred to as a mixed flow nozzle. One or both nozzles (whether mixed or split flow) may have a fixed or variable area. Whilst the described example relates to a turbofan engine, the disclosure may apply, for example, to any type of gas turbine engine, such as an open rotor (in which the fan stage is not surrounded by a nacelle) or turboprop engine, for example. In some arrangements, the gas turbine enginemay not comprise a gearbox.

10 9 1 FIG. 1 FIG. The geometry of the gas turbine engine, and components thereof, is defined by a conventional axis system, comprising an axial direction (which is aligned with the rotational axis), a radial direction (in the bottom-to-top direction in), and a circumferential direction (perpendicular to the page in theview). The axial, radial and circumferential directions are mutually perpendicular.

Coatings can be applied to a number of systems to improve their performance. Coatings can be applied to provide protection to a number of components material; these coatings can provide protection from, for example, corrosion, thermal properties. In some instances coatings may also be applied to improve the aesthetic appearance of a component.

One example of providing an engineering coating is the use of thermal barrier coatings for components within the heat zone of a gas turbine engine. Thermal barrier coatings are selected according to the properties of the materials that are used to form them. For example, one of the most common thermal barrier coatings used within the turbine and combustor section is yttria-stabilised zirconia (YSZ).

YSZ is a ceramic in which the cubic structure of zirconium dioxide is stabilized by the addition of yttrium oxide. Obtaining a stabilized coating is difficult because the volume of the zirconium structure needs to be increased to accommodate the yttrium. Therefore, deposition of the material is very difficult, as the material needs to be heated and deposited under defined conditions.

Similar problems are also present with the deposition of a number of other different material systems. This is because the materials need to be heated and then allowed to cool on the substrate in a defined way.

2 FIG. 100 100 110 110 140 145 is a schematic representation of an embodiment of a hyper-redundant manipulator spray systemfor depositing an engineering coating material on a component that is located within a gas turbine engine. The hyper-redundant manipulator spray systemhas a hyper-redundant manipulator arm. Movement of the hyper-redundant manipulator armis controlled by an actuator packthat may include a controller.

110 111 140 112 140 120 112 110 120 102 105 125 130 The hyper-redundant manipulator armhas a proximal end, i.e. the end that is proximal to the actuator back, and a distal end, i.e. the end this is distal to the actuator back. An end effectoris provided at the distal endof the hyper-redundant manipulator arm. The end effectorincludes tooling for applying the engineering coating materialto the component. That tooling includes an atomizing nozzle unitand a burner head.

100 150 102 105 150 102 125 102 150 155 150 125 150 125 102 150 140 150 125 155 The hyper-redundant manipulator spray systemhas a tankthat holds the engineering coating materialthat is to be deposited on the component. The tankmay take any suitable form. The engineering coating materialis in the form of a suspension. The atomizing nozzle unitis configured to receive a supply of the suspension of engineering coating materialfrom the tankvia a conduitthat runs between the tank and theand the atomizing nozzle unit. The tankis suitably located to supply the atomizing nozzle unitwith the suspension of engineering coating material. In the embodiment shown the tankis located adjacent the actuator packhowever in other embodiments the tankis located closer to the atomizing nozzle unitand therefore requires a shorter conduit.

125 100 102 150 155 172 102 125 3 FIG. The atomizing nozzle unitof the hyper-redundant manipulator spray systematomises the suspension of engineering coating materialthat it receives from the tankvia the conduitand provides a sprayof the engineering coating material. The atomizing nozzle unitis shown in more detail inand is further described with that figure below.

130 100 166 172 125 105 130 160 166 162 130 132 130 120 160 3 FIG. The burner headof hyper-redundant manipulator spray systemcombusts a flammable fluid from a supply of flammable fluid (not shown) to provide a flamethat propels the sprayof the engineering coating material formed by the atomizing nozzle uniton to the component (). The burner headhas at least one jetthrough which the combusted flammable fluid emerges as a flameand at least one air nozzle. The burner headis shown in more detail inand is further described with that figure below. The flammable fluid may be supplied from the supply of flammable fluid and through the hyper-redundant manipulator arm via a supply line () and into the burner headof the end effectorto supply the jet(s).

130 120 100 The flammable fluid may take various forms for its required purpose. The flammable fluid may be a gas, for example oxy-acetylene, propylene, liquified petroleum gas (LPG), propane, natural gas, hydrogen, MAPP gas (a stabilized mixture of methylacetylene, propadiene and propane), or a mixture thereof. The flammable fluid may be a liquid fuel, for example gasoline (e.g. petrol or diesel), kerosene, an aviation fuel, or a mixture thereof. Other suitable flammable fluids would be apparent to a person skilled in the art and may at least in part be determined by the configuration of the burner headof the end effectorof the hyper-redundant manipulator spray system.

172 166 160 160 1 FIG. The atomizing nozzle unit is configured to deliver the sprayof atomized of the engineering coating material at a desired angle with respect to the flamethat emanates from the jet. In the embodiment shown inthe engineering coating material is sprayed at an angle that is perpendicular, or at least substantially perpendicular, to the flame. In other embodiments the atomizing nozzle unit may be configured to spray the engineering coating material at some other angle to the flame, e.g. 30 degrees, 45 degrees or 60 degrees, typically spraying in the direction towards of the end of the flame that is furthest from the jetfrom which the flame emanates, or in line with, or at least substantially in line with the flame i.e. about 0 degrees.

162 130 166 160 166 172 102 105 162 The air nozzleof the burner headis positioned to feed the flameemanating from the jetwith oxygen and direct the flame, and the sprayof the engineering coating materialsupplied to the flame, towards the surface of the componentupon which the engineering coating material is to be deposited. The air nozzleis supplied with air from a suitable source (not shown), e.g. a pressurized gas container, a compressor, or ventilated through a conduit.

2 FIG. 130 160 130 160 In the embodiment shown inthe burner headhas a single jetbut in other embodiments the burner headhas a plurality of jets, e.g. two, three, four, five, six or more jets. In such embodiments the jets may be configured in any in any suitable configuration to obtain a desired heat profile for the burner head. For example, the jets may be configured so that flames from the jets overlap to create an enlarged high temperature area with a heated zone.

130 166 The burner headhas a suitable ignition source (not shown) to create the flamefrom the flammable fluid that is supplied to it. For example, the ignition source may be a piezo electric spark or a pilot light.

100 172 102 166 125 105 105 105 162 130 The hyper-redundant manipulator spray systemdirects the sprayof the engineering coating materialsupplied to the flamefrom atomizing nozzle unittowards and onto the surface of the componentthereby depositing the engineering coating material on the component. The engineering coating material will quickly dry or solidify to complete the desired engineering coating to the component. In some instances, largely depending on the engineering coating material, the air nozzleof the burner headmay be employed to provide a stream of air to assist in the drying or solidifying of the engineering coating on the component.

110 100 120 The successful application of the engineering coating material depends on the suitable manipulation of the hyper-redundant manipulator armof the hyper-redundant manipulator spray system. While that manipulation is controlled with the assistance of suitable actuators and supporting software, it nevertheless requires the guidance of one or more skilled operators of hyper-redundant manipulator equipment. In some embodiments that operation can be assisted by the use of suitable inspection equipment (not shown), for example one or more cameras or sensors that are provided in or with the end effector.

3 FIG. 2 FIG. 130 125 120 100 is a schematic representation of the burner headand the atomizing nozzle unitof the end effectorof the embodiment of the hyper-redundant manipulator spray systemthat is shown in.

201 112 110 130 130 132 166 164 160 168 162 160 166 160 168 105 102 168 162 105 The end effectoris connected to the distal endof the hyper-redundant manipulator arm. The burner headcombusts a flammable fluid from a supply of flammable fluid (not shown) that is connected the rear of the burner headby a supply line. The combusted flammable fluid provides a flamethat defines a combustion zonethat extends from the jet. A flow of airfrom the air nozzleis aligned in the direction of the jetor rather the direction of the flamethat emerges from the jetso that the flow of airimpinges upon the componentto be coated at the same point where the engineering coating materialis to be deposited or at least close to that point. The provision of the flow of airfrom the air nozzlecan also prevent thermal shock by helping to moderate the cooling rate of the atomised engineering coating material as it lands on the desired surface of the component, thereby facilitating a smooth deposition of the engineering coating material.

3 FIG. 130 162 162 168 In the embodiment shown inthe burner headhas a single air nozzlehowever in other embodiments the burner head has a plurality of air nozzles, e.g. two, three, four or more air nozzles, which are configured so flows of airimpinge upon the entire intended deposition area for the engineering coating material on the component.

3 FIG. 162 130 160 166 162 162 130 120 In the embodiment shown inthe air nozzleextends from a side of the burner headand bends in or at least towards the direction of the jetand the flamehowever in other embodiments the air nozzleor plurality of air nozzleis or are integrated into the burner heador the end effector.

162 130 168 105 102 As mentioned above, the air nozzleof the burner headsupplies a stream of aironto the componentwhere the engineering coating materialwill be applied. The air may be simply atmospheric air or it may contain one or more other gases e.g. nitrogen or an inert gas. The air may supplied at or near atmospheric pressure or it may be supplied at a high pressure.

168 120 120 120 111 110 110 The flow of aircan be provided in any suitable manner. It may for example be provided by an air pump (not shown) that is located within the burner heador within the end effectoror external to the end effector, e.g. located at or near the proximal endof the hyper-redundant manipulator arm, i.e. outside of the working environment of the hyper-redundant manipulator arm.

162 15 In some embodiments the air is supplied by the air nozzleor the plurality of air nozzles at a pressure of 120 to 1500 kPa (1.2 tobar), e.g. 400 to 600 kPa (4 to 6 bar). This provides a cooling effect that can facilitate the desirable formation of layers of engineering coating material on the component.

3 FIG. 3 FIG. 120 125 102 150 155 172 102 128 166 130 102 166 As shown in, the end effectorincludes an atomizing nozzle unitthat atomizes the suspension of engineering coating materialthat it receives from the tankvia the conduitand provides a sprayof the engineering coating materialvia an atomizing nozzle unit outletinto the flamegenerated by the burner head. In the embodiment shown inthe engineering coating materialis sprayed at an angle that is perpendicular, or at least substantially perpendicular, to the flame. In other embodiments the atomizing nozzle unit may be configured to spray the engineering coating material at some other angle to the flame, or in line with the flame.

2 3 FIGS.and 125 130 125 130 In the embodiment shown inthe atomizing nozzle unitis located alongside the burner headbut in other embodiments the atomizing nozzle unitand the burner headmay be integrated.

125 102 150 150 125 120 150 125 120 102 110 10 102 150 111 110 3 FIG. 2 FIG. The atomizing nozzle unitis supplied with engineering coating materialin the form of a suspension from the tank. The tankmay take any suitable form. In the embodiment shown inthe tank is cylindrical and is separate from the atomizing nozzle unitand indeed the end effectorhowever in other embodiments the tankmay be integrated with the atomizing nozzle unitand the end effector. The choice of configuration will generally depend on the volume of engineering coating materialthat is to be deposited on the component and the space available for the hyper-redundant manipulator armwithin the gas turbine engine. Where a large volume of engineering coating materialis required the tankmay be best located at or near the proximal end(see) of the hyper-redundant manipulator arm, i.e. outside of the working environment of the hyper-redundant manipulator arm.

102 105 125 155 110 150 157 102 150 157 157 157 150 3 FIG. 3 FIG. The engineering coating materialto be deposited on to the componentis supplied to the atomizing nozzle unitby the conduitthat runs along the most of the length of the hyper-redundant manipulator arm. In the embodiment shown inthe tankis supplied with an agitation devicethat stirs or otherwise agitates the suspension of engineering coating materialwithin the tankto ensure that the suspension remains at least substantially homogeneously. The agitating devicecan take any suitable form. In the embodiment shown inthe agitation devicehas paddle that rotates on a rotor to stir the engineering coating material. In other embodiments the agitation devicecomprises a transducer that shakes the tankinstead.

155 102 105 158 150 125 158 The conduitthat carries the engineering coating materialto be deposited onto the componentmay be provided with a flow regulatorthat serves to ensure a desired amount of the suspension of engineering coating material is supplied from the tankto the atomizing nozzle unit. The flow regulatorcan take many suitable forms and may include a rotameter.

125 102 150 127 125 105 127 120 120 111 110 110 168 162 130 The atomizing nozzle unitis supplied with the suspension of engineering coating materialfrom the tankand supplied with a flow of airfrom a source of air (not shown) that is used by the atomizing nozzle unitto atomize the suspension of engineering coating material that is to be deposited on the component. The air may be simply atmospheric air or it may contain one or more other gases, e.g. nitrogen or an inert gas. The flow of aircan be provided in any suitable manner. It may for example be provided by an air pump (not shown) that is located within the end effectoror external to the end effector, e.g. located at or near the proximal endof the hyper-redundant manipulator arm, i.e. outside of the working environment of the hyper-redundant manipulator arm. Alternatively it may be provided by the same source of air as the flow or airfrom the air nozzleof the burner head.

127 125 15 The flow of airto the atomizing nozzle unitmay be supplied from the source of air at a pressure from 120 to 1500 kPa (1.2 tobar), e.g. from 300 to 700 kPa (3 to 7 bar).

125 129 102 125 128 164 129 In some embodiments the atomizing nozzle unitincludes a pressure regulatorthat regulates the flow of atomized engineering coating materialthat is delivered by the atomizing nozzle unitvia the atomizing nozzle unit outletinto the combustion zone. The pressure regulatormay, for example, provide the atomized engineering coating material at a flow rate of from 0.5 to 50 ml/min, e.g. from 1 to 30 ml/min.

102 125 164 166 130 132 166 168 162 130 102 105 The atomized engineering coating materialthat exits the atomizing nozzle unitis directed into the combustion zonedefined by the flameprovided by the burner headby combusting the flammable fluid provided by the supply line. The flame, assisted in part by the flow of airfrom the air nozzleof the burner head, propels the atomized engineering coating materialonto the surface of the componentwhere it cools, typically in layers, to provide the desired engineering coating for the component.

110 100 120 105 In use the hyper-redundant manipulator armof the hyper-redundant manipulator spray systemmay be controlled so that the end effectormoves with respect to the component. In that way a strip of engineering coating can be applied to the component.

128 105 The quality of the engineering coating that is formed on a component is determined in part by maintaining a suitable distance between the atomizing nozzle unit outletand the surface of the componentupon which the atomized engineering coating material is deposited. This distance is the stand-off distance and is typically from 5 mm to 75 mm, e.g. from 15 mm to 40 mm.

4 FIG. 2 3 FIGS.and 2 3 FIGS.and 100 130 120 160 166 160 160 164 is a schematic representation presents a close-up top view of a second embodiment of the hyper-redundant manipulator spray system. that is shown inof the drawings. In this second embodiment the burner headof the end effectorhas three jetsand a flameemanates from each of those jets. The jetsare configured so that the flames coalesce and converge to form a single combustion zone. The second embodiment is otherwise identical to the first embodiment that is shown in.

4 FIG. 128 125 164 128 160 130 120 105 128 167 160 105 102 105 180 105 172 Inthe atomizing nozzle unit outletof the atomizing nozzle unitis shown positioned above a middle portion of the combustion zone. The atomizing nozzle unit outletis aligned substantially tangentially to a horizontal plane that passes through the three jetsof the burner headwhich helps to achieve a consistent and uniform deposition rate, especially as the end effectormoves in a direction that is in parallel with the surface of the componentthat is being coated with the engineering coating material. In this way the atomizing nozzle unit outletdispenses the engineering coating material into a flame path hot combustion zonecreated by the three jetsthat leads to the surface of the componentthat is to be coated. Once the atomised engineering coating materialstrikes the componentit forms a layer of an engineering coatingon the component, the thickness of the layer being dependent upon various parameters including the amount of time that the sprayof atomized engineering coating material is directed to the same point of the component and the volume of engineering coating material that is delivered to the component over that time.

110 120 105 182 105 180 105 4 FIG. As mentioned above, in use the hyper-redundant manipulator armmay be controlled so that the end effectormoves with respect to the componentthereby applying a strip of engineering coating to the component.shows a pathbeing traced laterally and linearly along the componentto build up a strip of engineering coatingalong the component.

4 FIG. 168 162 130 102 105 105 As also mentioned above (but not shown in), the presence of a flow of airfrom the air nozzleof the burner headcan moderate the cooling of the atomized engineering coating materialas it lands on the component, thereby avoiding thermal shock and facilitating a smooth deposition of engineering coating material on the component.

5 6 7 FIGS.,and 2 3 FIGS.and 125 162 130 depict polished cross-sectional micrographs of engineering coatings applied to a gas turbine engine component using the hyper-redundant manipulator spray system of. The engineering coating material used was a yttria-stabilised zirconia (YSZ), more specifically MSE PRO 8YSZ zirconium oxide yttria-stabilized nanoparticles that are commercially available from MSE Supplies LLC. This engineering coating material was prepared as a 25 wt. % suspension in ethanol, supplied to the atomizing nozzle unit at a flow rate of 5 ml/min, air was supplied to the atomizing nozzle unitat a pressure of 400 kPa (4 bar), and air was supplied to the air nozzleof the burner headat 600 kPa (6 bar) of pressure. The incorporation of YSZ nanoparticles is evident in the engineering coatings produced. The presence of semi-molten and unmolten deposited zones was observed and confirmed by zirconium elemental mapping by electron dispersive spectroscopy.

5 FIG. 2 4 FIGS.to 105 depicts a polished cross-sectional micrograph of a coating applied to a gas turbine engine componentusing the hyper-redundant manipulator spray system of.

6 FIG. 2 4 FIGS.to 105 201 202 depicts another polished cross-sectional micrograph of the coating applied to the gas turbine engine componentusing the hyper-redundant manipulator spray system of. The micrograph shows that the coating has a dense vertically cracked structure. Two such cracks, one large, small crackand one large vertical crack, are highlighted.

7 FIG. 2 4 FIGS.to 105 203 depicts yet another polished cross-sectional micrograph of the coating applied to a gas turbine engine componentusing the hyper-redundant manipulator spray system of. A vertical crackin the coating is highlighted.

120 128 105 102 Having a relatively short stand-off distance, i.e. the distance between the end effector(or more specifically the atomizing nozzle unit outlet) and the componentto which a engineering coating materialis applied, impacts the thermal state of the particulates. The nanosized YSZ particulates remain in a hot state upon impact, which promotes sintering upon contact with the component. This sintering phenomenon gives rise to a dense coating.

168 162 130 164 167 168 6 7 FIGS.and The flow of airfrom the air nozzleof the burner headplays an important role in steering the path of the atomized engineering coating material into the combustion zone, and more particularly into the flame path hot combustion zone. The flow of airalso enables a steep thermal gradient across the component, which is primarily responsible for the cracks observed in the engineering coatings shown in.

162 128 5 7 FIGS.to Close coordination between the stand-off distance and the air nozzlecan create the right conditions for generating dense vertically cracked structures. As mentioned above, the stand-off distance between the atomizing nozzle unit outletand the component is typically from 5 mm to 75 mm. In the experiments that provided the results depicted inthe distance was 25 mm.

8 FIG. 300 2 4 is a flow diagram of a methodfor depositing a coating on a component that is located within a gas turbine engine e.g. using the hyper-redundant manipulator spray system shown in FIGS. toto.

310 300 100 110 10 102 105 150 155 125 132 130 145 In stepof the methodthe hyper-redundant manipulator spray systemis provided and set up for use. The set up can involve one or more of the following steps: initiating the hyper-redundant manipulator arm, positioning the hyper-redundant manipulator arm in the vicinity of the workspace within the gas turbine engine, preparing the suspension of the engineering coating materialthat is to be deposited on the component, supplying the tankwith the suspension of the engineering coating material, connecting the conduitto the atomizing nozzle unit, connecting supply lineto the burner head, and/or loading a pre-programmed routine into the controllerfor the hyper-redundant manipulator arm.

320 110 100 145 In stepthe hyper-redundant manipulator armof the hyper-redundant manipulator spray systemis positioned within the workspace in which the component is located. The positioning may be carried out manually or controlled automatically, e.g. by the controller. depending on the location of the component within the gas turbine engine.

330 160 130 120 166 166 145 130 In stepa flammable fluid is supplied to at least one jetof the burner headof the end effectorof the hyper-redundant manipulator spray system and combusted to form a flame. The flow of the flammable fluid to the jet(s) may be controlled by a valve to control the flamecreated by combusting the flammable fluid. The valve may be manually controlled or automatically controlled, e.g. by the controller. As mentioned above the flammable fluid may take various forms for its required purpose. It may be a gas or a mixture of gases. It may be a liquid fuel or a mixture of liquid fuels. The choice of flammable fluid may at least in part be determined by the configuration of the burner head.

340 125 102 166 129 145 In stepthe atomizing nozzle unitis supplied with a suspension of an engineering coating materialand a spray of atomized engineering coating material is directed into the flame. The flow of the suspension of an engineering coating material to the atomizing nozzle unit can be controlled manually or automatically, for example using a pressure regulator. Any automatic control may be provided via the controller.

The engineering coating material may take any form that is suitable for the engineering coating material to be supplied to the hyper-redundant manipulator spray system as a suspension. It may be an environmental barrier coating material from which an environmental barrier coating may be formed on a component or a thermal barrier coating material from which a thermal barrier coating may be formed on a component.

5 7 FIGS.to 2 The choice of engineering coating material will generally depend on the component to be coated and its location within the gas turbine engine. The engineering coating material may be a yttrium-stabilized zirconia (YSZ), e.g. as used to provide the engineering coatings shown in. The engineering coating material may be or also include a mullite, an aluminium oxide (e.g. alumina), a cerium oxide (e.g. CeO), a rare-earth zirconate, a metal-glass composite, a ytterbium silicates, or a MCrAlY alloy.

150 The suspension of engineering coating material may be formulated as required to provide the desired engineering coating for the component concerned. The suspension may contain, for example, from 1 to 50 wt. %, 1 to 40 wt. %, 1 to 30 wt. %, 1 to 20 wt. %, or 1 to 10 wt. % of the engineering coating material. The solvent may be, for example, ethanol, propanol, acetone or water, depending on the engineering coating material, the desired viscosity, and the desired combustion. The suspension of engineering coating material may be heated in the tankto optimise its viscosity and/or to allow a greater weight percentage of the engineering coating material in the suspension to obtained. The tank my be heated by any suitable method, for example electrical resistance heating. The suspension of engineering coating material contain sub-micron or even nano size particulates to achieve durable nano-structed engineering coatings.

50 In some embodiments the engineering coating material is an ethanol-based suspension feedstock of yttrium-stabilized zirconia. The suspension feedstock may have a sub-micron particle size (D) of about 500 nm.

130 120 130 The burner headof the end effector, may be configured or positioned to direct a spray or stream of atomized engineering coating material perpendicular, or at least substantially perpendicular, to the surface of the component to be coated. Alternatively, the burner headmay be position to direct the spray or stream otherwise angled relative to the substrate as desired.

350 120 166 105 120 145 In stepthe end effectoris moved along a path to deposit the engineering coating material from the flameon the component. The movement of the end effectormay be carried out manually or controlled automatically, e.g. by the controller, depending on the location of the component within the gas turbine engine. The path may be linear, curved, spiral or according to some other discrete pattern.

120 110 120 110 145 120 The end effectorand the hyper-redundant manipulator armmay be configured to remain in a fixed orientation relative to the component. Alternatively, the orientation of the end effectorand/or the hyper-redundant manipulator armmay change relative to the component, either by manual control or by automatic control, e.g. by the controller. The end effectormay oscillate relative to the substrate.

110 120 The hyper-redundant manipulator armmay be configured or controlled so that the end effectorcan alter its lateral or longitudinal position relative to the component whilst moving across the component and depositing the engineering coating material thereon.

120 145 120 The speed of the movement of the end effectormay be constant or may be varied as desired, either by manual control or by automatic control, e.g. by the controller. Controlling the amount of time that the end effectoris positioned over a particular area of the component can determine the amount of engineering coating material that is deposited on the desired surface(s) of the component.

100 The hyper-redundant manipulator spray systemmay be configured or controlled to provide a thicker coating over one part of the component and a thinner coating over another part of the component. For example, a central area of the coating may be formed to be thicker than the edges of the coating to allow the coating to blend with any existing coatings, e.g. to provide a clean repair.

360 160 130 102 125 120 110 330 360 In stepthe supply of the flammable fluid to the at least one jetof the burner headand the supply of the suspension of the engineering coating materialto the atomizing nozzle unitis turned off. The end effectorand/or the hyper-redundant manipulator armmay be moved to a second position and steps-performed again for the new position. When the end effector is no longer required to deposit the engineering coating on a component or surface of a component within the workspace, the hyper-redundant manipulator arm can be removed from the workspace.

The hyper-redundant manipulator spray system of the present disclosure may be used for various processes including crankshaft reconditioning or conditioning, corrosion protection, fouling protection, thermal conductivity or electrical conductivity modification, wear control, or repair.

It will be understood that the invention is not limited to the embodiments above-described and various modifications and improvements can be made without departing from the concepts described herein. Except where mutually exclusive, any of the features may be employed separately or in combination with any other features and the disclosure extends to and includes all combinations and sub-combinations of one or more features described herein.